Mutual diffusion coefficients, density, and viscosity of aqueous solutions of new polyamine CO2 absorbents

The mutual diffusion coefficients of aqueous solutions of new polyamine CO2 absorbents, namely 3-(methylamino)propylamine, diethylenetriamine, N,N,N′,N′-tetramethylethylenediamine, and tetramethyl-1,3-diaminopropane at different concentrations were measured at temperatures from 303.15 to 323.15 K using the Taylor dispersion technique. Empirical and semi-theoretical models such as a modified Snijder et al. equation, UNIDIF equation, and a free-volume relation based on the rough hard-sphere theory were used to represent the experimental diffusion coefficient data as function of temperature and amine concentration. Densities and viscosities of the aqueous solutions, which were used in the calculation of diffusion coefficients, were also measured. The obtained density and viscosity data were correlated with temperature and amine concentration using a Redlich–Kister-type and Vogel–Tamman–Fulcher equation, respectively. The predicted density, viscosity, and diffusion coefficient data were in reasonable agreement with the experimental data, suggesting that the measured properties were satisfactorily represented by the applied models.